Field enhancement around metal nanoparticles and nanoshells: A systematic investigation
Field enhancement around metal nanoparticles and nanoshells: A systematic investigation
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DOI：
10.1021/jp8060009
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发表时间：
2008-10-09
影响因子：
3.7
通讯作者：
Tanabe, Katsuaki
中科院分区：
文献类型：
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作者：
Tanabe, Katsuaki
已知金属纳米颗粒和由金属壳和介电核组成的纳米壳由于表面等离子体激元而显著增强其周围的入射电磁场。在准静态极限下，利用经验波长依赖的介电常数计算了球形金属纳米颗粒和纳米壳的场增强因子。场增强因子对各种参数的依赖性，如波长，距离纳米粒子/纳米壳，金属元素，介电核材料，周围介质，和核和壳之间的直径比，进行了研究。有趣的是，对于任何贵金属壳和电介质核的组合，峰值场增强因子随着核壳直径比接近0.9而变得最大。作为参数优化的结果，人们发现，具有聚四氟乙烯核与核/壳直径比为0.88的Ag纳米壳在其附近的水中表现出1400的峰值场增强因子。
Metal nanoparticles and nanoshells consisting of metal shells and dielectric cores are known to significantly enhance incident electromagnetic fields around themselves due to surface plasmons. The field enhancement factors were calculated for spherical metal nanoparticles and nanoshelis in the quasistatic limit using empirical wavelength-dependent dielectric constants. Dependence of the field enhancement factor on various parameters, such as wavelength, distance from the nanoparticle/nanoshell, metal element, dielectric core material, surrounding medium, and diameter ratio between the core and the shell, was investigated. Interestingly the peak field enhancement factor becomes largest with core-to-shell diameter ratio at similar to 0.9 for any combination of noble metal shell and dielectric core. As a consequence of the parameter optimization, it was found that an Ag nanoshell with a Teflon core with a core/shell diameter ratio of 0.88 exhibits a peak field enhancement factor of 1400 in its vicinity in water.